Safety valve, in particular for cooking plate gas and related mounting method

ABSTRACT

The invention concerns a safety gas valve ( 1 ) provided with a safety closure ( 23 ) and an operating lever ( 12 ) for the closure. The lever ( 12 ) is mounted mobile in rotation about an axis L in a cavity ( 34 ) circulating the gas and comprises two tabs ( 122, 123 ) extending transversely to the axis L, one driving and the other driven. The driving tab ( 122 ) drives the lever in rotation, and hence the driven tab ( 123 ) which is secured thereto, in response to a stress A when the valve is opened. The driven tab ( 123 ) enables to push back the safety closure ( 23 ) into an opening position allowing the gas to flow in the valve. If both tabs extend along respective mutually perpendicular directions, the lever ( 12 ) enables the cocking movement to return by 90 degrees. Said device reduces the thickness of the valve body, in particular for its fixing into a built-in cooking plate.

[0001] The present invention relates to improvements made to safetydevices for gas burners, particularly in a cooking appliance, andparticularly those suited to be mounted on a built-in hob equipped withgas burners. The invention is aimed more specifically at improving asafety device for a gas burner according to the preamble of claim 1.

[0002] The gases used as fuel to produce energy, and which when mixedwith air under certain conditions produce explosive mixtures, aredangerous and require the use of safety devices. In particular, valvesfor cooking appliances employing gas burners, in addition to having aflow-regulating control valve for the gas, are also equipped with suchdevices. These in particular allow the gas supply to be cut off as soonas the gas is not being burnt in a burner.

[0003] These safety devices generally employ a thermocouple, arranged inthe burner, to monitor its correct operation and a safety shutter which,in the event of failure, allows any circuit supplying gas to the burnerto be shut off. When the burner is operating normally, the heat from theflame causes a difference in electric potential in the thermocouple.This potential difference is used to activate an electromagnet whichkeeps the safety shutter against a compressed spring; when the shutteris in the open position, that is to say it does not prevent the gas fromflowing through the supply circuit. The safety device is in the setposition, ready to perform its function. Thus, in the event of failure,for example if the gas is no longer being burnt in the burner, andtherefore near the thermocouple, the potential difference disappears,the electromagnet is no longer activated and the safety shutter is freeto move under the impulse of the spring, and this drives it into theclosed position to shut off the gas supply. The same thing happens whenthe gas flow-regulating control valve is closed, that is to say that itprevents gas from being supplied to the burner, because then no flamecan heat up the thermocouple.

[0004] The simple manipulating of the valve by an operator, that is tosay the opening of the supply-regulating control valve to a greater orlesser extent, therefore has no influence on the supply to the burner aslong as the device is not set, that is to say as long as the safetyshutter is in the closed position. There are therefore mechanicalsetting devices that allow the shutter to be kept open, by deliberateaction on the part of the operator, at least until the burner has beenlit and enough of a potential difference has been created to activatethe electromagnet.

[0005] A rotary knob is generally situated above a casing of the hob.Through it being turned in a horizontal plane, it allows the extent towhich the valve is opened to be adjusted, that is to say it allows thedesired gas flow rate to be set. This knob also, through a verticalupward movement, allows the safety device to be set. It is a verticalcontrol rod, fixed under the knob or operated indirectly by the knob,which transmits the setting instruction, that is to say the upwardmovement, to the setting device.

[0006] Safety and setting devices are generally included in the body ofthe valve and arranged in the supply circuit, this making it possible tomake savings in terms of compactness and to limit the number of gasseals required between excessively numerous components of the supply.

[0007] A casing of a built-in hob must be fairly slim, generally thirtymillimeters thick, in order to comply with the standards of kitchenfurniture manufacturers. Most of the components of the valve aretherefore arranged horizontally inside the casing. This is the case ofthe shutter which moves horizontally under the opposing influences ofthe setting device and of the spring. The setting device has thereforeto allow the vertical control movement of the control rod to beconverted into a horizontal movement for opening the shutter.

[0008] A first type of safety valve comprises a setting device one partof which transmits the vertical translational movement to a crankedlever, articulated for rotation, which converts the vertical movementinto a horizontal movement. Such a device entails arranging severalparts and their articulations with precision within the body of thevalve. These arranging operations cannot be done by automatic means butmust be performed manually. In order to use these parts, the valve bodyis manufactured in two bits, by casting or forging, one to accommodatethe parts and the other to act as a lid for the first. A seal is alsoarranged between the two bits. A valve such as this is expensive and itssetting device is delicate in proportion to its complexity.

[0009] A second type of valve comprises a setting device which uses tworamps each mounted for translation, sliding one along the other, and theslopes of which are designed to convert the vertical movement of oneramp into a horizontal movement of the other. Such a device also hasdisadvantages. The precision of its production and of its mounting hasto be very high given the small travel of the ramps. Further, as oneramp does not bear on the other axially, it generates radial forces andwear in bearings for guiding them and the rubbing-together of the rampscauses them both to wear. This wear may cause valve malfunction.

[0010] Document GB 2 261 495 describes a safety device of the typementioned above, in which the setting lever is in the form of a solidand rigid cylindrical bar, of one piece with its two radial arms whichare also solid and rigid. Such an arrangement allows no offset betweenthe respective travels of the actuating rod and of the safety valveshutter rod. This demands both high precision in the manufacture of thesetting lever and of its arms, which makes it an expensive part, and inthe adjustment of the parts during assembly, which increases the cost ofmanufacture.

[0011] A European standard dictates that a safety valve be capable ofperforming at least 40,000 operations without failing. All the partshave therefore to have good resistance to the friction to which they aresubjected. Significant friction leads therefore to high costs ofmanufacture of these parts.

[0012] It is an object of the invention to propose a fuel supply valvecomprising a setting device that is simple and reliable to operate, forconverting the control movement, for example vertical, of a control rodinto a setting movement, for example horizontal, for the safety device.

[0013] According to the invention, a safety device as mentioned above ischaracterized in that the setting lever is elastically deformable intorsion, by virtue of which the driving means can effect an over-travelwith respect to the driven means.

[0014] If the tabs run in roughly mutually perpendicular respectivedirections, they allow a control movement to be converted into aperpendicular setting and thrusting movement. The lever axis willadvantageously be arranged at right angles to the directions of thecontrol and thrusting movements.

[0015] In order to limit the number of seals and special purposearrangements, the device will be included in a cavity of a fuel supplycircuit, preferably one that already exists, in a body of the valve. Inorder to minimize pressure drops as the fuel flows through the cavity,the setting lever will have a small cross section. It may be made ofbent sheet metal. For use in a gas supply, the lever will need to beinsensitive to a temperature of 150° C., that it might experience eitherbecause of the proximity of the burner or because of the flow of gas,that is to say that its behavior must not be affected by a temperatureof 150° C. or lower.

[0016] Making the lever from bent sheet metal makes it possible toguarantee a small cross section perpendicular to the direction of gasflow, that is to say transversely with respect to the supply circuit.This cross section and the small pressure drops it creates means thatthe supply circuit need not be oversized in order to allow the gaseousmixture to flow therein under satisfactory conditions.

[0017] Bent stainless steel sheet gives, for the desired cross section,both good lever integrity and the desired elasticity. Of course, thelever may also be made from other materials which will give the sameelasticity for cross sections compatible with the flow of gases throughthe supply circuit.

[0018] Advantageously, the setting lever will comprise self-positioningmeans for positioning itself in the cavity and the shape of the cavitywill be tailored to accommodate these self-positioning means. The cavitywill, for example, comprise a closed end comprising self-centering meansfor an anterior end of the lever along a theoretical lever axis. Anorifice at the opposite end to the closed end along the theoretical axisand opening to the outside of the valve body will serve for introducingthe lever into the cavity. The orifice will be closed by a shut-offstopper comprising self-centering means for a posterior end of the leveron the theoretical lever axis and sealing the cavity against theoutside.

[0019] To guarantee the position of the lever in the cavity when fittingthe shut-off stopper, precentering means may be provided on the leverfor precentering the lever in the cavity. These precentering means keepthe posterior end of the lever in a position close to the theoreticalaxis, which position allows it to collaborate with the self-centeringmeans of the stopper, when the latter is being fitted, when the lever isno longer accessible from outside the valve body. This arrangementallows the lever to be mounted “blind” in the cavity. As a preference,the self-centering means in the closed end of the cavity and on thestopper will act as bearings for the rotation of the setting lever, thishaving the purpose of simplifying the design and manufacture of thesetting device.

[0020] Other particulars and advantages of the invention will becomefurther apparent from the description hereinafter, relating to somenonlimiting examples.

[0021] In the attached drawings:

[0022]FIG. 1 is a partial depiction, in perspective and in section, ofone possible configuration of a valve according to the invention, thesafety device of which is in the closed position;

[0023]FIG. 2 is a depiction of the valve of FIG. 1, the safety device ofwhich is in the open position;

[0024]FIG. 3 is a perspective view, on a larger scale, of a settinglever as used in the valve of FIGS. 1 and 2; and

[0025] FIGS. 4 to 6 illustrate a method for mounting the lever of FIG. 3in a valve body according to the invention.

[0026]FIGS. 1 and 2 depict, in section and in perspective, a body 10 ofa safety valve according to the invention, designed to be mounted in ahob using gas. The body comprises a safety device 20 mounted in a gassupply circuit. The safety device 20 is depicted in a closed position inFIG. 1, that is to say that it prevents gas from flowing through thesupply circuit. The safety device 20 is depicted in an open position inFIG. 2.

[0027] The supply circuit comprises, in succession, in the body 10, aninlet pipe 31 letting gas into an inlet chamber 32, a safety orifice 33at the intersection of the inlet chamber and of an intermediate cavity34, the intermediate cavity, a regulating chamber 35, a regulatingorifice 36 and a gas outlet 37 for the outlet of gas to a burner, notdepicted.

[0028] The body 10 is output as a section piece the section of which istailored to the shape of the body, that is to say that the section pieceis output transversely in slices the thickness of which is more or lessthat of the body. The supply circuit is created by making holes in thesection piece. The holes are secant to one another in pairs so as toensure the continuity of the supply circuit. They are more or lesscylindrical and are blind, that is to say do not pass through the body.The holes have a starting orifice where the hole has been started on thesection piece and a closed end axially opposite the starting orifice,where the hole stops. This closed end consists at least of a wall of asecant hole. The starting orifices may be used as orifices forintroducing components of the valve into the supply circuit.

[0029] For the clarity of the drawing, the inlet pipe 31 has beendepicted as opening vertically into the inlet chamber 32. However, inorder to restrict the thickness of the valve body, this pipe ispreferably horizontal. It brings the gas from a gas distribution lineset for distributing gas to each of the valves of the hob, as far as theinlet chamber.

[0030] Apart from a thermocouple positioned in the burner, the safetydevice 20 is arranged in the inlet chamber. It is therefore upstream inthe supply circuit. It is thus able, by cutting off the flow of gasdownstream of the safety orifice if necessary, to optimize safety. Thesafety device consists of a more or less cylindrical housing 21 and of apiston 22 mounted to slide, along an axis of revolution S of the housing21, through one of the walls of the housing. The housing includes anelectromagnet, not depicted, which, when activated by the thermocouple,causes the piston to enter the housing. The housing also contains aspring, not depicted, which tends to extract the piston from thehousing.

[0031] One end of the piston 22, external to the housing, is equippedwith a shutter 23. If the electromagnet is not active, that is to say ifthe potential difference in the thermocouple is insufficient, theshutter 23 is kept in or brought into a closed position (see FIG. 1) onthe safety orifice 33 by the action of the spring. Thus, there is nolonger any communication for the gas in the inlet chamber with thesupply circuit downstream of the safety orifice 33.

[0032] Under normal operating conditions, to activate the electromagnetgas needs to be burnt in order to increase the temperature in the burnerand create a potential difference in the thermocouple that powers theelectromagnet. However, in order to be able to burn gas in the burner,therefore near the thermocouple, the gas flow-regulating control valveregulating the flow of gas through the safety valve needs to be open andthe shutter needs to be in an open position to allow the gas to passinto the supply circuit, downstream of the safety orifice 33, as far asthe burner.

[0033] It is a mechanical setting device 11 which, when theelectromagnet is not active, allows the shutter 23 to be brought intoand kept in the open position, that is to say it counters the action ofthe spring that tends to keep the shutter in the closed position.

[0034] When the safety device is set, using the setting device, theshutter is therefore in an open position, which means that the gas inthe inlet chamber can pass through the safety orifice 33 into theintermediate cavity 34 and then beyond, if the control valve is open. Ifthe gas is burnt properly in the burner, the potential difference arisesin the thermocouple under the action of the increase in temperature. Assoon as the potential difference is sufficient, that is to say that theforce exerted by the electromagnet on the piston overcomes the forceexerted thereon by the spring, the piston is kept retracted into thehousing through the action of the electromagnet. The action of thesetting device on the shutter becomes superfluous and may be released.

[0035] The setting device, the operation of which is described later on,comprises a setting lever 12, a spacer piece 13, and a control rod 14.

[0036] The spacer piece 13 is arranged longitudinally through the safetyorifice 33. It has a shape tailored for its guidance at the periphery ofthe safety orifice and so that it can slide therein. It has a crosssection that allows gas to flow through the orifice 33, between theinlet chamber 32 and the intermediate cavity 34 when the shutter 23 isin the open position. In the example chosen, the safety orifice iscylindrical and the spacer piece has a cross section in the shape of athree-branch star 133. The branches serve to guide the spacer piecealong the interior wall of the safety orifice. The gas can flowlongitudinally between the branches of the star. The spacer piece runslongitudinally between two domed ends 131, 132, the first 131 facingtoward the intermediate cavity 34 and the second 132 facing toward theinlet chamber 32. In the example described, the spacer piece is made offiber-reinforced plastic, giving it significant strength for a smallcross section at a lower cost than metal. The inlet chamber, the safetyorifice and the spacer piece are more or less coaxial with the axis S,depicted in FIGS. 5 and 6, of the housing 21.

[0037] The valve serves to regulate the flow of gas through the burner,and therefore to regulate the speed at which the burner heats. A knob16, for actuating the rod 14, is accessible by an operator to controlthe valve. The rod, more or less cylindrical of axis T, is arrangedvertically. A control valve, not depicted, makes it possible, by closingoff the regulating orifice 36 to a greater or lesser extent, to alterthe flow of gas in the burner. The operator can regulate the flow rateby turning R the knob 16 about a vertical axis, and this has the effectof moving the regulating control valve past the regulating orifice 36,and therefore of closing it off to a greater or lesser extent. Theregulating chamber comprises sealing means, beyond the control valve andbefore the control knob 16, that is to say near the starting orifice forthe regulating chamber, around the rod 14. Thus, if the valve is open,the gas can flow into the regulating chamber only from the intermediatecavity to the outlet 37 through the regulating orifice 36, without beingable to escape out of the supply circuit.

[0038] In FIG. 1, the axis of rotation R of the knob 16 is depicted ascoinciding with the axis T of the rod 14. However, the knob is notgenerally fixed to the rod 14 that it controls then only indirectly, andthe rod 14 may be arranged to have just a translational movement alongthe axis T. The axis of rotation of the knob 16 may therefore differfrom the axis T.

[0039] The control lever 12 is made of thin stainless steel sheet. Thissheet has been cut, bent and shaped to give it the shape more speciallydepicted in FIG. 3. The lever is of fairly elongate shape; it comprisesa beam 121 running longitudinally between an anterior end 128 and aposterior end 129. The beam 121 has a V-shaped cross section about alongitudinal fold 41 which gives the beam certain rigidity in terms oflongitudinal bending. The ends 128, 129 of the beam 121 are cut to theshape of points, and between each of the points define an axis L for thelever. The lever axis L is more or less coincident with the longitudinalfold 41 of the beam 121.

[0040] The setting lever 12 also comprises a driving tab 122 and adriven tab 123. The driven tab runs transversely from a longitudinaledge 42 of the beam, near the anterior end 128. The driven tab 123 runstransversely from a longitudinal edge 43 of the beam, the opposite edgeto the edge 42, near the posterior end 129.

[0041] Two fins 124 run transversely, one from the edge 42 and the otherfrom the edge 43, more or less in the continuation of the V formed bythe beam, one facing the other, in close proximity to the posterior end129. The fins are precentering means for the posterior end when thelever is being mounted in the intermediate cavity.

[0042] In the example described, the lever is mass-produced from a sheetmetal strip. For that, it comprises an indexing hole 126 and anappendage 127. The hole 126 serves to index the sheet in the machinesfor manufacturing the lever. The appendage 127 is a vestige of theportion of sheet metal connecting the future lever, while it is beingmanufactured, to another future lever next to it in the sheet.

[0043] The intermediate cavity 34 (see FIG. 1) comprises a startingorifice which serves as an orifice 341 for introducing the lever 12 intothe intermediate cavity, and a closed end 343. The closed end comprisesa coaxial cone 348 coaxial with the intermediate cavity. Once the leverhas been introduced into the intermediate cavity 34, this cavity isplugged by a stopper 342 forcibly fitted into the starting orifice 341to seal against gas between the inside and the outside of the supplycircuit. The stopper 342 comprises a cone 349 roughly coaxial with thecavity 34, once the stopper has been fitted into the starting orifice341. The cone 348 of the closed end and the 349 of the stopperrespectively complement the anterior 128 and posterior 129 ends of thebeam 121. They respectively define, for each of the ends, an anteriorbearing 348 and a posterior bearing 349. The bearings define atheoretical axis of rotation for the lever 12 in the cavity 34 and actas stops for the longitudinal positioning of the lever in the cavity 34.When the lever 12 is in place in the cavity 34, between the bearings348, 349, the theoretical axis is more or less coincident with the leveraxis L.

[0044] The tabs 122, 123 are arranged on the lever 12 so that, in aposition in which the lever is in place in the cavity 34, the drivingtab 122 runs roughly diametrically to the regulating chamber 35 and inalignment with the regulating chamber, and so that the driven tab 123runs more or less diametrically to the safety orifice 33 and inalignment with said orifice and with the inlet chamber 32.

[0045] We shall now describe the operation of the setting device withreference to FIGS. 1 and 2. According to a widespread principle ofoperation of a safety valve suited to a gas hob, pressure by theoperator on the knob 16 makes it possible, by moving the knob 16 and therod 14 whose translation it drives vertically downward in the directionA parallel to the axis T, to set the safety device 20. Return means, forexample a compression spring, allow the rod 14 and the knob 16 to bereturned, in the opposite direction to A, to a position of rest.

[0046] In FIG. 1, the control rod 14 is in its rest position, that is tosay it exerts no action on the setting device 11. The shutter 23 is in aclosed position and no gas flows through the supply circuit between theinlet pipe 31 and the outlet 37, independently of the closing-off of theregulating orifice 36. To light the burner downstream of the valve 1,the operator opens the valve, that is to say the control valve closingoff the regulating orifice 36, via an appropriate turning R of the knob16 and pushes down on this knob to move the control rod translationallydownward, vertically, along A. During this translational movement, alower end 141 of the rod 14 comes into contact with the driving tab 122.A domed lower end will advantageously be anticipated.

[0047] The axis T of the rod 14 is more or less perpendicular to thelever axis L, and the two axes are not secant. Thus, while thetranslational movement A continues, the driving tab 122 is at the sametime driven downward and the setting lever 12, to which the driving tabis connected in terms of movement, begins a swinging movement on B aboutthe lever axis L. The driven tab 123, it too connected in terms ofmovement to the lever 12, is driven in the movement of the lever, towardthe safety orifice. During this swinging movement, the driven tab ispressed against the first domed end 131 of the spacer piece 13.

[0048] The lever axis L and the axis S of the safety device are notsecant and are more or less perpendicular. Thus, while the swingingmovement B continues, the spacer piece begins a horizontal translationalmovement which will press its second domed end against the shutter 23.As its travel continues, under the impulse of the rod 14 relayed by thesetting lever 12, the spacer piece 13 pushes the shutter 23 back into anopen position.

[0049] The movements described are halted when the stopper 23 or thepiston bearing the shutter encounters a first stop provided for thatpurpose. It is preferable to provide a second stop to limit the travelof the rod. A setting lever as set out in the example has a certaintorsional elasticity about the lever axis L. This elasticity makes itpossible to absorb an over-travel of the rod 14 along A, therefore anover-travel of the driving tab along B, although the safety device isalready in abutment against the first stop and the rod has not reachedthe second stop. Thus, the driving tab 122 continues its travel along B,about the lever axis L, while the driven tab 123 is more or lessimmobile. The over-travel thus absorbed makes it possible to concealdimensional discrepancies and/or play resulting either from the methodsand tolerances with which the valve was manufactured, or from valvewear. The over-travel is therefore desirable and can be definedconstructively. As a preference, the elasticity of the lever will bedesigned to be compatible with this over-travel, that is to say to makeit possible to absorb it entirely. The setting lever also, by virtue ofthis over-travel, acts as a damper for the setting device, and thisgives the valve a longer life and is more comfortable for the user. Inthe example described, the elasticity of the lever about the lever axisL increases with the elongation of the beam 121.

[0050] When the shutter is in the open position, the safety device is inthe set position, that is to say that if gas flows in the direction ofthe arrows F as illustrated in FIG. 2, in the supply pipe as far as theburner, all that is required is for the gas to be lit, automatically ormanually, so that it can be burnt and a potential difference can becreated in the thermocouple that is sufficient for the device to becomeset.

[0051] Once the safety device is set, the operator can release hispressure on the control knob 16. The rod then reverts to its restposition for which the setting device does not force the shutter toremain in the open position, that is to say that the setting deviceallows the shutter to move freely between its open and closed position.Thus, the device remains set until it is made to close, for example ifthe gas supply to the burner is cut off.

[0052] To limit the lateral loads in the translating parts of thesetting device, that is to say the rod 14 and the spacer piece 13, thetabs are given a shape such that a force that one of them transmits toone of the translating parts is applied more or less along the axis ofthis part, for example to a vertex of a domed end of the part. Inparticular, the shape of the tab is such that, at a point of contact ofthe vertex with a contact surface of this tab, the contact surface isalways tangential to the domed end and perpendicular at this point tothe axis of the translating part.

[0053] The swinging of the lever as described generates little frictionand does not appreciably alter the pressing force needed to operate thecontrol knob 16.

[0054] We shall now describe a method for mounting the setting lever 12in the intermediate cavity 34, particularly with reference to FIGS. 4 to6, drawn in planes perpendicular to the theoretical axis defined by thecavity 34. FIGS. 4 to 6 illustrate two steps in the mounting of thelever. FIG. 6 illustrates the mounted lever, once the stopper 342 hasbeen fitted. During the fitting of the stopper 342 in the startingorifice 341, it is not possible using mechanical or manual means to makesure that the lever 12 is correctly positioned in the cavity 34. Thelever and the method are therefore designed to guarantee perfectself-positioning of the lever in the cavity.

[0055] It can be seen, as illustrated particularly in FIG. 6, that inorder to come into contact with the first domed end 131 of the spacerpiece 13 at the axis S, the driven tab extends beyond the lever axis Lover a distance greater than a radius of the intermediate cavity. Thus,the posterior end of the lever needs to be offset when the driven tab ispassed through the introduction orifice 341, as illustrated in FIG. 4.

[0056] In opposition to this, the anterior end 128 of the lever 12 ispositioned exactly in its bearing 348. For that, the body 10 is kept ina mounting position, inclined enough for the vertex of the cone thatacts as an anterior bearing 348 to be a low point for the cone. Thus, asthe lever is introduced into the cavity, when the anterior end of thelever is placed in the anterior bearing, there is no risk of said endcoming out of the bearing, or of it doing so during the subsequentmounting operations.

[0057] In the mounted position, care is taken to ensure that therelative positions of the lever axis L and the axis of the safety systemS are such that, once the anterior end has been positioned in theanterior bearing, all that is required is for the posterior end of thelever to be released for the driven tab to position itself facing thesafety orifice 33 simply under the action of gravity, as illustrated inFIG. 5. As the stopper 342 is fitted, the holding of the posterior end129 can no longer be ensured by external means. To make sure that theposterior end will position itself correctly in the posterior bearing.349, the lever is held in a precentered position, resting on the fins124 under the action of its self weight alone. These fins are designedso that, in the precentered position, the posterior end is close enoughto the lever axis L enters the posterior bearing 349 as the stopper 342is fitted into the introduction orifice 341.

[0058] The fins are short enough that they do not rub against the wallsof the intermediate cavity 34 when the setting lever 12 swings about B(see FIG. 6). Thus, they do not center the lever perfectly but simplyprecenter it (see FIG. 5). Furthermore, the fins 124 have not to impedethe offsetting of the posterior end when passing through theintroduction orifice. For this, as illustrated in FIG. 4, the fins forma dihedral the vertex of which is opposed to the direction of extensionof the driven tab 123, that is to say that the driven tab sits insidethe dihedral angle.

[0059] Of course, the invention is not restricted to the example whichhas just been described and many variations can be made to this examplewithout departing from the scope of the invention.

[0060] The body of a valve according to the invention is not necessarilyoutput as a section piece. For more complicated shapes, for example fora valve comprising several outlets each supplying one ring of amulti-ring burner, it may be produced by casting.

[0061] This valve may be used on the front face of an oven. In thiscase, the control direction is more or less horizontal and the pushingdirection may be at right angles but does not have to be vertical.

[0062] This type of valve can also be adapted to fuels other thandomestic gas, for example fuel oil.

[0063] The lever may also have a different shape, for example thedriving and/or driven tabs may be replaced by, or included in, otherrespective driving and/or driven means. For example, driving means maybe a cylinder rather than a tab.

[0064] The lever can also be manufactured using other techniques, forexample casting or assembling. It may be made of plastic.

1. A safety device for a gas burner, particularly in a cookingappliance, comprising a safety valve provided with a safety shutterincluded in a circuit for supplying said burner with gas, and with adevice (11) for mechanically setting said shutter, comprising: a settinglever (12) mounted so that it can move in rotation (B) about a leveraxis (L), driving means (122), secured to the lever and running roughlytransversely to the lever axis, able to drive said lever in rotation inresponse to a setting command (A), and driven means (123), secured tothe lever and running roughly transversely to the lever axis, able topush said shutter (23) into a setting position that allows gas to flowthrough said burner's supply circuit, characterized in that the settinglever (12) is elastically deformable in torsion, by virtue of which thedriving means (122) can effect an over-travel with respect to the drivenmeans (123).
 2. The safety device as claimed in claim 1, characterizedin that the setting lever is mounted in a cavity (34) of the gas supplycircuit.
 3. The safety device as claimed in claim 1 or 2, characterizedin that the setting lever comprises a beam (121) and in that the drivingmeans extend from said beam near a first end (128) of the beam and inthat the driven means extend from said beam near a second end (129) ofthis same beam.
 4. The safety device as claimed in claim 3,characterized in that the lever axis is defined by the first and secondends of the beam.
 5. The safety device as claimed in any one of claims 2to 4, characterized in that the lever comprises self-positioning means(124, 128, 129) for positioning itself in the cavity.
 6. The safetydevice as claimed in any one of claims 1 to 5, characterized in that thecavity (34) has a closed end (343) and an orifice (341) plugged by astopper (342) and in that the lever is mounted to rotate between a firstbearing (348) in the closed end and a second bearing (349) in thestopper.
 7. The safety device as claimed in claims 5 and 6,characterized in that the self-positioning means comprise means (124)for precentering one end (129) of the beam near the orifice.
 8. Thesafety device as claimed in claim 7, characterized in that theprecentering means are fins running transversely to the lever axis nearthe end that is to be precentered.
 9. The safety device as claimed inany one of claims 6 to 8, characterized in that at least one of thefirst and second bearings is designed to collaborate with some (128,129) of the self-positioning means.
 10. The safety device as claimed inclaim 9, characterized in that at least one end (128, 129) of the beamis in the shape of a point to collaborate with a cone-shaped bearing(348, 349), particularly so as to self-position said end in saidbearing.
 11. The safety device as claimed in any one of claims 1 to 10,comprising a control rod (14) mounted in translation to transmit thesetting command (A), characterized in that the driving means and the rodare designed so that a contact force of the driving means on the rod istransmitted more or less along the axis of said rod.
 12. The safetydevice as claimed in any one of claims 1 to 11, comprising a spacerpiece (13) functionally associated with the safety shutter (23) andmounted in translation to receive the setting command, characterized inthat the driven means and the spacer piece are designed so that acontact force of the driven means on the spacer piece is transmittedmore or less along the axis of said spacer piece.
 13. The safety deviceas claimed in any one of claims 1 to 12, characterized in that the leveris made of cut and bent sheet metal.
 14. The safety device as claimed inany one of claims 1 to 13, characterized in that the driving meansand/or the driven means comprise a tab (122, 123) secured to the lever.